1. Technical Field
The present invention relates to a technique for image processing.
2. Related Art
In recent years, among video display apparatuses such as a liquid crystal television, a plasma television, and a projector, there is known a video display apparatus with specifications of high resolution far surpassing high-definition television. In such a video display apparatus that displays a high-resolution video, a system for dividing the entire screen of a video into plural areas and processing the areas with plural processors in parallel is frequently adopted. In the system in the related art, the processors independently perform video processing for video data that the processors handle, respectively. However, in such a system, in the case of processing for applying arithmetic operation referring to data of peripheral pixels of pixels as in filter processing, in some portions of pixels at ends of the divided screens, there is no peripheral pixel data. Therefore, there is inconvenience that the entire screen cannot be completely subjected to the filter processing. As a method of solving such inconvenience, JP-A-10-304184 (Patent Document 1) is known.
In an image processing device disclosed in Patent Document 1, image data is read out from an image storing unit in which the entire area of an image is stored. A dividing and input unit divides the image into plural areas. Plural pipeline processing units process the divided areas in parallel. When the pipeline processing units need to refer to peripheral pixels, the dividing and input unit divides necessary peripheral pixels such that the divided areas overlap and inputs the peripheral pixels to the pipeline processing units.
However, in the method disclosed in Patent Document 1, it is not assumed that multistage filter processing is performed. If it is attempted to perform the multistage filter processing, work for reading out data from the image storing unit, applying the filter processing in the pipeline processing units, and then storing the data in the image storing unit again is repeated many times. Therefore, an amount of access to the image storing unit and a processing amount of the pipeline processing units increase.